The present invention relates generally to the field of biopsy devices and the methods of using such devices. More specifically, it relates to a device and method for accessing a targeted site of pathologically suspect tissue mass within a patient""s body, so as to facilitate the taking of a specimen of the tissue mass.
In diagnosing and treating certain medical conditions, such as potentially cancerous tumors, it is usually desirable to perform a biopsy, in which a specimen of the suspicious tissue is removed for pathological examination and analysis. In many instances, the suspicious tissue is located in a subcutaneous site, such as inside a human breast. To minimize surgical intrusion into the patient""s body, it is desirable to be able to insert a small instrument into the patient""s body to access the targeted site and then extract the biopsy specimen therefrom.
After removing the tissue specimens, additional procedures may be performed at the biopsy site. For example, it may be necessary to cauterize or otherwise treat the cavity which results from tissue specimen removal to stop bleeding and reduce the risk of infection or other complications. Also, it may be advantageous to mark the site for future surgical procedures should pathological tests performed on the biopsy specimen indicate surgical removal or other treatment of the suspected tissue mass from which the specimen was removed. Such marking can be performed, for example, by the apparatus and method disclosed and claimed in co-pending U.S. patent application Ser. No. 09/343,975, filed Jun. 30, 1999, entitled xe2x80x9cBiopsy Site Marker and Process and Apparatus for Applying It,xe2x80x9d which is hereby incorporated by reference in its entirety.
Electrosurgical techniques have been used in a variety of circumstances, including certain types of biopsy procedures. In electrosurgery, high frequency electrical energy is applied through an active electrode to patient tissue. The electrical energy flows through the tissue from the active electrode to a return electrode which is in contact with the patent""s tissue and which may be on the exterior of the patient""s body or intracorporeally disposed. Typically, the return electrode is attached to the patient at a point remote from where the primary or active electrode contacts the tissue. The tissue adjacent the primary electrode is ablated, to form an opening in the tissue. An electrosurgical biopsy instrument is disclosed and claimed in U.S. patent application Ser. No. 09/159,467 for xe2x80x9cElectrosurgical Biopsy Device and Method,xe2x80x9d assigned to the assignee of the subject application, and which is hereby incorporated by reference in its entirety.
This invention is directed to a biopsy device that provides ready access to a targeted tissue site within a patient""s body and provides for the separation and capture of a tissue specimen from the target tissue site. More specifically, the biopsy device provides for a split tissue specimen which greatly facilitates a accurate pathological examination upon its removal from the patient""s body.
The biopsy device of the invention generally includes an elongated probe having a proximal end and a distal end and an inner lumen extending therein. A distal probe section is provided which has transverse dimensions less than adjacent portions of the probe and which has one and preferably a plurality of apertures in a wall thereof in fluid communication with the probe""s inner lumen. A circular electrode or a pair of opposed semicircular electrodes are slidably disposed about the probe member and are configured for longitudinal translation along a length and preferably the entire length of the small dimensioned distal probe section. The electrode or electrodes are disposed in a plane or planes which are perpendicular and transverse to the longitudinal axis of the probe.
The proximal end of the probe is configured to allow the inner lumen of the probe to be connected to a vacuum source, so that when a vacuum is applied to the inner lumen, tissue adjacent to the small dimensioned distal probe section is pulled into contact with the distal probe section through action of the vacuum through the apertures thereof and thereby fix the tissue specimen to the distal probe section. With the tissue of the specimen secured to the distal probe section, the circular or semicircular electrodes powered by high frequency (RF) electrical power may then be advanced distally to thereby separate the tissue specimen from the tissue bed to which the tissue is secured and supported. The probe and the tissue specimen secured thereto may then be withdrawn from the patient.
In present embodiment of the invention, the biopsy device has a thin, arcuate shaped distal electrode connected to the distal end of the probe and spaced distally therefrom as disclosed in copending applications Ser. No. 09/477,255, filed on Jan. 4, 2000 and Ser. No. 09/057,303 filed on Apr. 8, 1998, which are hereby incorporated herein in their entirety. The distal arcuate electrode lies in a plane that is parallel to and generally passes through a longitudinal axis of the elongated probe. The cordal dimension of the distal electrode is at least the same dimension as the diameter of the distal end of the elongated probe, preferably greater than the diameter of the distal end to ensure that an opening is made through the tissue to the target site and through the suspicious tissue by the electrode which is large enough to allow the biopsy device to be readily advanced. Moreover, because the distal electrode passes through the desired tissue for the specimen, it makes a planar cut through the desired specimen, so that when the circular or semicircular electrodes are advanced over the small dimensioned distal probe section to cut the specimen from the supporting tissue, the specimen is split or is separated into two half specimens.
In a presently preferred embodiment the biopsy device is provided with an outer sheath that is slidably disposed along a length of the probe so as to cover the small dimensioned distal probe section during advancement through tissue and to open and allow specimen tissue to be pulled into contact with the small dimensioned distal probe section when a vacuum is applied to the inner lumen of the probe and the tissue of the specimen is severed from the adjacent supporting tissue by the longitudinal translation of the RF powered circular or semicircular electrodes. The electrodes may be secured to the distal end of the sheath so that the specimen(s) can be separated from the adjacent tissue while the sheath closes over the small dimensioned distal probe section thereby capturing the severed specimen(s) within the interior of the sheath. The biopsy device may then withdrawn from the patient, and once withdrawn, the specimen or specimen halves secured to the distal probe section maybe removed for subsequent pathological examination.
The distal electrode is connected by means of an electrical conductor which extends to the proximal extremity of the probe, preferably through the inner lumen of the probe to a high frequency, e.g. RF, electrical power. The proximal circular electrode or semicircular electrodes may have their own supporting structure or may be supported as described above from the distal end of the outer sheath. An elongated electrical conductor connects the proximal circular electrode or a pair of elongated electrical conductors connects the proximal electrode to a high frequency, e.g. RF, electrical power which may be the same power source which powers the distal electrode or a separate power source. When the proximal circular electrode or semicircular electrodes are secured to the distal end of the outer sheath, the conductor(s) which connects the proximal electrode(s) may extend through the wall of the outer sheath. The high frequency power for the proximal electrode or electrodes is usually greater than the high frequency power required by the distal electrode. However, generally the proximal electrode(s) are operated at a different time in the procedure so a single power source can be readily programmed to operate at the different electrical power levels required by the electrodes of the present device.
The probe, the proximal electrode and the outer sheath are preferably configured as a disposable unit which may be hand operated or powered by a hand unit connected to a suitable controller.
These and other advantages of the invention will become more apparent from the following detailed description of the invention and the accompanying exemplary drawings.